Automatically compensating hair blending device

ABSTRACT

Method and apparatus for blending hair which includes a plurality of cutting reliefs for capturing the hair to be blended wherein the reliefs are of arcuate configuration and disposed in the stationary cutting teeth. The configuration of the reliefs are such in respect to the stroke of the moving cutting teeth that a predetermined area of the relief is not traversed by the moving cutting teeth. A percentage of the hair in the relief will pass to the back of the relief and not be cut against shearing edges disposed within the relief. The area of the relief which is untraversed by the moving cutting teeth is constant resulting in the cutting of a percentage of thicker hair passing into the relief than thinner hair thus automatically compensating the blending effect according to the thickness of the hair being cut.

United States Patent [72] Inventors Glenn R. Willey 1181BellemeadDr-ive, Warminster, Pa. 18974; 1

William B. Fuller, Upperstate Road, Chalfont, Pa. .18914; Vernon W.Biesecker, 1171 Bellemea drive, Warminster, Pa.

1 1 18740 [2]] Appl. No. 791,655 [22] Filed Jan. 16, 1969 [45] PatentedMar. 23, 1971 [54] AUTOMATICALLY COWENSATING HAIR {5 4 l BLENDING DEVICE2,001,206 5 1935 Matthes 2,008,631 7/1-935 Udkovich 30/195 2,035,6323/1936 Andis 30/195 FOREIGN PATENTS 1,010,722 11/1965 GreatBritain30/195 be blended wherein the reliefs are of arcuate configuration anddisposed in the stationary cutting teeth. The configuration of thereliefs are such in respect to the stroke of the moving cutting teeththat a predetermined area of the relief is not traversed by the movingcutting teeth. A percentage of the hair in the relief will pass to theback of the relief and not be out against shearing edges disposed withinthe relief. The area of the relief which is untraversed by the movingcutting teeth is constant resulting in the cutting of a percentage ofthicker hair passing into the relief than thinner hair thusautomatically compensating the blending effect according to thethickness of the hair being cut.

AUTOMATICALLY COMPENSA'I'ING HAIR BLENDING DEVICE BACKGROUND OFINVENTION The present invention concerns hair cutting devices and, moreparticularly, hair cutting devices of the type which blend the hairbeing cut.

In the process of cutting hair, the bulk of the hair is first removedand the hair generally brought into the form desired. Following this,the hair is trimmed and finally blended to give the final appearance ofthe hair style.

The blending operation is a very important step in the hair cuttingprocess and is the final step in which the ends of the hair are cut toirregular lengths so as to lay one over the other to avoid theappearance of a step cut. This process is not to be confused withthinning of hair in which a percentage of the hair is cut close to thescalp rather than the ends.

In any blending operation, the volume of the hair must be considered. Inthe case of thicker hair, a greater degree of blending is required forproper appearance than thinner hair.

The blending operation may be accomplished either by hand in which acomb and blending scissors are used by power operated shears. Blendingby hand is a time consuming and tiring job and, as well, requiresv agreat deal of skill to be done properly. Mechanically operated shearsfor blending are less time consuming and tiring but those presentlyavailable today suffer from a serious drawback in not being able tocompensate for the relative volume and thickness of hair .being blended.

OBJECTS AND SUMMARY OF INVENTION The principle object of the presentinvention is to improve mechanically powered hair cutting blendingshears by providing cutters which will automatically vary the blendingeffectin proportion to the volume of the hair being cut.

It is a further object of the present invention to provide blendingcutters according to the principle object in which the degree ofautomatic compensation can be varied slightly, by the speed at which thecutters are passed through the hair in one embodiment and by the angleat which used in another embodiment.

Thepresent invention carries out the foregoing objects by utilizing aplurality of reliefs in a pair of oscillating cutting blades. Thereliefs may be in either or both cutting blades and both blades mayoscillate, although in a preferred embodiment, one of the blades isstationary and the reliefs are in the stationary cutting blade.

The reliefs include shearing edges therein and the hair being blended isadapted to pass into the reliefs. The cross'sectional area of thereliefs is proportioned in respect to the extent to which the movingcutter blade passes over the relief such that there will always be apredetermined percentage of the crosssectional area of the relief whichis untraversed by the oscillating cutting blade. This predetermined areais so adjusted that, in the case of very thin hair, all of the hairwhich passes into the relief will be forced to the back part of therelief which is untraversed by the cutting blade thus resulting inshearing of very little of the thinner hair. In the case of hair ofincreasing volume, the predetermined area will remain constant andthereof a greater percentage of the hair must be sheared against theshearing edges of the blade in each oscillation of the cutting blade.The result is an automatic compensation in the extent of blending of thehair depending upon the volume of the hair being cut.

In another embodiment of the invention, forwardly extending cuttingedges one disposed between the reliefs-to make the blending effect ofthe cutting attachment sensitive to the rate at which the attachment ispassed through the hair.

. In a third embodiment, the untraversed area of each relief isincreasingly diminished toward the rear of the cutting teeth to make theblending effect greater for hair passing toward the rear of theattachment. In this manner, the automatic blending effect can beslightly varied depending upon the angle at which the cutting attachmentpasses through the hair.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of the blendingattachment of the present invention in place on a motor driven shears;

FIG. 2 is an enlarged view showing in detail a portion of the cuttingblades of the attachment of FIG. 1;

FIG. 3 is a view of the cutting blades of FIG. 2 in full stroke leftposition;

FIG. 4 is an enlarged detailed view of a second embodiment of cuttingblades of the present invention providing for adjustrrient of theautomatic blending effect depending upon the rate of movement throughthe hair; and

FIG. 5 is an enlarged detailed view of a third embodiment of the cuttingblades of the present invention which also adjust the blending etfectdepending upon the angle of use.

DETAILED DESCRIPTION OF INVENTION A preferred embodiment of the presentinvention is shown in FIG. 1 of the drawings. The cutting attachment 10is designed to be used with a motor driven clipper handle I I and isinterchangeable with other I conventional cutting attachments normallyused with the handle II. The attachment 10 includes an oscillating uppercutting blade 12 and a stationary lower cutting blade 13. The blades 12and 13 are suitably supported and joumaled one to the other to permit arelative oscillating motion between the blades I2 and I3. The cuttingattachment is also retained in the handle II by a spring clip (notshown) and the cutting blades are driven through a conventional forkarrangement. To this point, the cutting attachment and handle II arelike convention cutting shears well known to those skilled in the artand for that reason the details thereof have not been illustrated.

The improved design which constitutes the present invention resides inthe configuration and relative cooperation of the cutting teethassociated with the oscillating and stationary cutting blades. In theembodiment of invention shown in FIG. I, the oscillating cutting blade12 includes a plurality of elongate cutting teeth 14. The cutting teethI4 are rounded at their ends 15 and include a sharp lower edge I6thereon against which the hair to be cut is sheared.

The lower stationary cutting blade I3 includes a plurality of cuttingteeth I7. These teeth 17 are, likewise, rounded at their ends I8 toprovide for smooth passage of the cutting teeth through the hair. Eachof the cutting-teeth includes a plurality of reliefs I9 which are groundinto the cutting blades. Each relief is undercut so as to provide ashearing edge 20 along the perimeter of the relief.

In operation, the oscillating cutting teeth 14 move back and forthacross the reliefs 19 disposed on either side of the cutting teeth. Inaccordance with the invention, the stroke of the cutting teeth isadjusted so as to pass only partially across the relief.

As the cutting attachment passes through the hair to be blended, thehair will pass between the oscillating cutting teeth' and into thereliefs as the oscillating cutting teeth pass through their intermediateposition as shown in FIG. 2. Further, as the oscillating cutting teethI4 move to the limit of their left and right stroke, the hair capturedin the reliefs I9 will be forced toward the back of the reliefs.

In the case of verythick hair, the volume of hair in the relie willresult in some of the hair being sheared between the shearing edgeI6'and the flanks-of the shearing edge 20 as a result of the volume andresistance of the hair in being moved to the rear of the relief. As thecutting tooth I4 continues to move to the limit of its stroke, the areaof the relief in which the hair is captured continues to decrease andadditional hair will be sheared against the shearing edges I6 and 20until the cutting tooth has reached the limit of its stroke as shown inFIG. 3. At this point, the hair left uncut will be that which may occupythe untraversed area of the relief 19.

In the case of thinner hair, there is less overall resistance by thehair in moving into the rear of the relief 19 and consequently lessshearing action occurs as the cutting, blade moves across the relief.Likewise, in the case of thinner hair,

there is overall less hair to occupy the relief and at the end of thecutting stroke, that hair which will remain uncut in the untraversedarea of the relief will represent a greater proportion of the hairinitially passing into the relief. This occurs inasmuch as thecross-sectional area of the relief, which is untraversed, remainsconstant irrespective of the volume of the hair being blended.

From the foregoing, it will be appreciated that the percentage of hairwhich will be cut is, for all practical purposes, dependent upon therelative volume of the hair passing into the reliefs thus resulting inan automatic variation of the blending effect depending upon thethickness of the hair.

The above described operation of the cutting attachment of the presentinvention is dependent upon certain relationships being maintainedbetween the length of the stroke of the cutting teeth 14, the widthbetween the cutting teeth 17 and the configuration of the reliefs 19.This may be understood by first considering that, for any given spacingbetween the cutting teeth 17, there will be exposed to the cuttingreliefs 19 a given strip or width of hair. This given strip of hair willbe evenly divided by the cutting tooth I and captured in the variousreliefs 19 on either side of the tooth 15. Thus initially, the totalarea of each relief 19 must be large enough to accommodate all of thehair presented to the relief in the case of the thickest hair. Secondly,the untraversed area at the end of the cutting stroke must be soproportioned to effect the minimum percentage of blending desirable forthe thinnest hair. Lastly, the degree of blending will remain constantfor the same volume of hair regardless of the configuration of therelief if the relief is so constructed that the total cross-sectionalarea of the relief is reduced to a predetermined percentage of thatinitial cross-sectional area at the end of the cutting stroke.

Turning specifically to the embodiment of FIGS. 2 and 3, it is to benoted that the cutting blades do not employ any cutting edge on theforward edge of the cutting teeth 17. Accordingly, once the hair hasbeen blended to that percentage controlled by the relative volume of thehair, which occurs within a relatively few strokes of the cutting blade,the continued presence of the cutting attachment in the hair does notresult in any significant further cutting of the hair. Thus, in theembodiment of FIGS. 2 and 3, the relative speed of the cutting bladesand the speed at which the cutting attachment moves through the hairdoes not produce any significant difference in the extent of blendingwhich occurs.

In some applications, it is desirable to vary the percentage of blendingfor any given volume of hair to suit the hair of the particularindividual. The cutting attachment of FIGS. 2 and 3 may be modified asshown in FIG. 4 to provide such a variation to a limited degree. In theembodiments of FIG. 4, the reliefs 19 are spaced by forwardly projectingcutting edges 23 having shearing edges 24 at the leading edge thereof.In this arrangement, all of the hair will not pass into the relief 19but, instead, a percentage thereof will be sheared across the projectingcutting edge 23 as the cutting teeth pass across the shearing edge 24.

Due to the presence of the shearing edge 24, the speed of the cuttingteeth 14 and the speed at which the cutting attachment is passed throughthe hair now does become a factor in the percentage of hair which is cutfor any given volume of hair. The relative porportions between the widthof the cutting edge 24 and the configuration of the relief I9 willdetermine the sensitivity of the cutting attachment to the speed of thecutting blades and the rate at which the attachment is passed throughthe hair. The optimum attachment has been found to proportion to therelative cutting on the forward edge 24 to l030 percent of the cuttingoccurring within the reliefs.

In the embodiment of FIG. 4, the best performance of the cuttingattachment has been found wherein the reliefs 19 are arcuate and therelief is traversed by the cutting blade 14 to one-half the depth of thearc. The best sensitivity in respect to speed of the attachment is foundwherein the width of the forwardly projecting edges 24 is within therange of 30 to 60 percent of the diameter of the arcuate reliefs.

The automatic variation of the blending effect found in the embodimentof FIG. I may also be varied slightly by modifying the attachment ofFIG. I as shown in FIG. 5. In this embodiment, the reliefs 25 are ofdecreasing depth toward the rear of the cutting tooth 17. The effect isto decrease the percentage of initial cross-sectional area of the reliefwhich is untraversed as the hair passes toward the rear of the cuttingtooth. Thus an increasingly greater blending effect will occur for thesame volume of hair dependent upon the extent to which the hair passesto the rear of the tooth 17. In turn. the angle at which the cuttingattachment is passed through the hair will control the amount of hairpassing into the rear position of the attachment. Accordingly. theblending effect can be varied in the attachment of FIG. 5 depending uponthe angle at which it is used.

The same effect can be accomplished as that of FIG. 5 where the width ofthe cutting tooth I4 is increased toward the rear and the depth of thecutting relief held constant.

The configuration of the relief 19 has been shown in FIGS. 25 as arcuateand is the preferred form. However, so long as the basic relationshipsare maintained between the stroke. teeth width and relief configurationas discussed above. other forms of relief may be used and may includesuch configurations as V-shaped reliefs. Whatever form of relief isused, it is preferable that the relief have a shearing edge thereinwhich converges inwardly of the relief. A converging shearing edgeprovides a better cutting or scissors action on the hair during thecutting stroke. Nevertheless, the present invention can be applied to arelief having straight parallel sides.

The foregoing invention has been described in respect to particularembodiment thereof shown in the drawings. It will be apparent thatvarious modifications of the above described embodiments of theinvention will be apparent to those skilled in the art, it is thereof tobe understood that such modifications can be made without departing fromthe spirit and scope of the invention as set out in the appended claims.

We claim:

1. A hair blending device which automatically controls the percentage ofhair cut as a functionof the relative volume of the hair being blendedcomprising;

a first cutting blade having a plurality of cutting teeth;

a second cutting blade having a plurality of cutting teeth and supportedin respect to said first cutting blade for relative oscillating shearingmovement therebetween;

a plurality of reliefs in selected ones of said cutting teeth into whichat least a portion of the hair to be blended passes, said reliefs beingof a given cross-sectional area and including shearing edges thereinagainst which a portion of the hair within said relief is cut; and

means limiting the relative movement of said first and second cuttingblades one to the other such that a predetermined percentage of thegiven cross-sectional area of said reliefs are untraversed during theoscillating shearing movement of the first and second cutting blades,said predetermined percentage being equal to the area capable of beingoccupied by that quantity of hair represented by the minimum percentageof blending for the thinnest hair, whereby a greater percentage ofthicker hair will be cut within each relief during the blending actionthan thinner hair.

2. The hair blending device of claim I in which one of said cuttingblades is a stationary cutting blade.

3. The hair blending device of claim 2 wherein all of said reliefs aredisposed within the stationary cutting blade.

4. The hair blending device of claim I wherein each of said reliefswithin said cutting teeth are separated one from another by forwardlyprojecting cutting edges.

5. The hair blending device of claim I wherein each of said cuttingreliefs are of decreasing cross-sectional area inwardly of said cuttingblade to provide a scissors action between the cutting blades.

6. The hair blending device of claim 5 wherein said reliefs are ofarcuate configuration,

7. The hair blending device of claim 6 wherein each of said the arc.reliefs within said cutting teeth are spaced one from the other 10, Th hi ble ding device of claim 1 wherein the by forwardly projecting cuttingedges.

8. The hair blending device of claim 7 wherein the width of theforwardly projecting cutting edges is within the range of 30 to 60percent of the diameter of thearcuate reliefs.

- 9. The hair blending device of claim 6 in which the cutting bladestraverses the arcuate reliefs to one-half of the depth of predeterminedarea of each of said reliefs remaining untraversed at the end of theshearing movement of said cutting blades increasingly diminishes towardthe rear of said cutting blades.

LII

1. A hair blending device which automatically controls the percentage ofhair cut as a function of the relative volume of the hair being blendedcomprising; a first cutting blade having a plurality of cutting teeth; asecond cutting blade having a plurality of cutting teeth and supportedin respect to said first cutting blade for relative oscillating shearingmovement therebetween; a plurality of reliefs in selected ones of saidcutting teeth into which at least a portion of the hair to be blendedpasses, said reliefs being of a given cross-sectional area and includingshearing edges therein against which a portion of the hair within saidrelief is cut; and means limiting the relative movement of said firstand second cutting blades one to the other such that a predeterminedpercentage of the given cross-sectional area of said reliefs areuntraversed during the oscillating shearing movement of the first andsecond cutting blades, said predetermined percentage being equal to thearea capable of being occupied by that quantity of hair represented bythe minimum percentage of blending for the thinnest hair, whereby agreater percentage of thicker hair will be cut within each relief duringthe blending action than thinner hair.
 2. The hair blending device ofclaim 1 in which one of said cutting blades is a stationary cuttingblade.
 3. The hair blending device of claim 2 wherein all of saidreliefs are disposed within the stationary cutting blade.
 4. The hairblending device of claim 1 wherein each of said reliefs within saidcutting teeth are separated one from another by forwardly projectingcutting edges.
 5. The hair blending device of claim 1 wherein each ofsaid cutting reliefs are of decreasing cross-sectional area inwardly ofsaid cutting blade to provide a scissors action between the cuttingblades.
 6. The hair blending device of claim 5 wherein said reliefs areof arcuate configuration.
 7. The hair blending device of claim 6 whereineach of said reliefs within said cutting teeth are spaced one from theother by forwardly projecting cutting edges.
 8. The hair blending deviceof claim 7 wherein the width of the forwardly projecting cutting edgesis within the range of 30 to 60 percent of the diameter of the arcuatereliefs.
 9. The hair blending device of claim 6 in which the cuttingblades traverses the arcuate reliefs to one-half of the depth of thearc.
 10. The hair blending device of claim 1 wherein the predeterminedarea of each of said reliefs remaining untraversed at the end of theshearing movement of said cutting blades increasingly diminishes towardthe rear of said cutting blades.